Intercommunication telephone system.



No. 809,929. PATENTED JAN. 16, 1906.

l R. M. BEARDL INTERGOMMUNICATION TELEPHONE SYSTEM.

APPLICATION FILED NOVA, 1902.

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R. M. BEARD. I INTERCOMMUNIGATION TELEPHONE SYSTEM.

APPLICATION IQIILBD NOVA, 1902.

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RICHARD M. BEARD,

INTERCOIVHVIUNICATION No. 809.929. Specification of Application filedNovember 4,

To all whom it may concern:

Be it known that I, RICHARD M. BEARD, a citizen of the United States ofAmerica, and a resident of New York, in the county of New York and Stateof New York, have invented certain new and useful Improvements inIntercommunication Telephone Systems, of which the following is aspecification.

My invention relates generally to telephone systems, and specifically toa secretservice or private line system of intercommunication from onestation to another without the necessity of a central office and withoutthe serious objection of a third party being able through anymanipulation of his own telephone apparatus or switching devices tolisten in while two other parties are in communication. No complicatedor unusual mechanism is needed in my system, privacy being securedthrough the disposition of circuits. The number of subscribers islimited only by the amount of space at the disposal of each party forthe location of the installation and by the inconvenience of leadinginto each station the necessarily large number of wires, or cablecontaining the leading-in wires, for the telephone.

I have found that the intercomiminication systems in present operation,either by reason of securing no privacy to conversations or by reason ofcomplicated and easily-disordered automatic devices to prevent same, arenot adapted to the needs of groups of men in a particular line ofbusiness-such as stock-brokers, financiers, and dealers in valuablecommodities where telephonic com municatlon is of limited value unlessabsolutely private. The number of such users requiring private-lineservice among themselves seldom exceeds ten.

My system is especially designed to meet the needs of parties requiringabsolutely private telephonic intercommunication. It is equally adaptedto be used as a house system in hotels, apartment-houses,department-stores, general oflices, private dwellings, mills, factories,hospitals, or other in stitutions, war vessels, or ships of any classand may be used as a community system in villages, ship-yards, mines,and other isolated districts where telephonic interservice is desiredwithout the expense of maintaining a central office and operators. Inany of the above-mentioned uses secret service is of value only 1n alesser degree than in the case Letters Patent.

1902. Serial No. 130,054.

Patented Jan. 16, 1906.

of the parties for which my system is spe cifically designed.

Generally the organization comprising my invention consists of thecombination of telephone, signaling, and switching apparatus located ateach of three or more stations and a system of interconnecting linescomprising independent wires for respectively connecting the apparatusat each one of the stations with the apparatus at each one of theremaining stations. The disposition of the local circuits and apparatus,with the exception of the keys, which are intermediary between thedifferent groups of apparatus and the interconnecting lines, is in twogeneral groups, and each of the groups is connected to a separate pairof contact-springs on the keys by an independent pair of wires. One ofthe general groups may be termed the telephone and signal-sending group,and by means of switching-contacts located in and forming a part of theapparatus comprised in this group talking and si naling may bealternately done over the same pair of wires leading to the keys. Theother of the two general groups may be termed the signalreceiving group,and the apparatus of this group consists of visual signals and anaudible signal, which are so connected together through switchingcontacts forming a part of the visual mechanisms that the audible signalmay operate simultaneously with any one of the visual signals over thesame pair of wires leading to the keys. The function of the keys locatedat each station is to connect the circuits loading to each of the otherstations alternately with either of the two general groups of apparatus.In order that this'may be done, the moving arms of the keys, which arevirtually double-pole doublethrow switches, are connected to the pair ofwires leading to the station to which each key respectively corresponds.Of the other two pairs of contacts, with each of which the moving armsare alternately in contact, the one is connected to the one of thegeneral groups, while the remaining pair of contacts is connected to theother of the two general groups of apparatus.

In view of the limited space on the sheets of drawings only threestations are represented completely.

Figure 1 is a general view of the complete system in a normal conditionapplied to three stations and showing the common return method 01interconnecting lines. Fig. 2 shows the complete interwiring for connecting ten stations, in which a common returnwire is also used. Thetelephone apparatus and local wiring for each station'is omitted fromthis drawing.

The apparatus and local wiring at each of the stations shown in Fig. 1is exactly the same. Some of the apparatusas, for example, thetransmitter and receiver-is shown as exterior elevations; but most of itis represented diagrammatically and typically.

The diiierent station's shown in the draw ings and indicated,respectively, as Sta. 1, Sta. 2, and Sta. 3 may be known as station 1,station 2, and station 3, while there may be further stations at Sta. 4,Sta. 5, Sta. 6, Sta. 7, Sta. 8, Sta. 9, and Sta. 10. At each of thestations there is a connecting-strip, (indicated at Sta. 1 as cs, atSta. 2 as 08 at Sta. 3 as 08 and so on the connectingstrips areindicated at each of the remaining stations.) On each of theconnecting-strips there is a set of terminals or binding-posts, and theterminals are numbered from left to right beginning with 0 and omittingthe number corresponding to the number of the strip i. 6., the number ofthe station at which the strip is located. For example, the

terminals on the connecting-strip cs are numbered from left to right, 02 3, &c. The terminals on the strip 08 are numbered 0 1 3, &c., whilethe terminals on the strip 08 are numbered 0 1 2, omitting 3, and so on.The common wire is numbered 0-0 and is connected to the terminalnumbered 0 at each of the connecting-strips. The wire numbered 12 isconnected at cs with terminal 2 and at 08 with terminal 1 and is theindependent wire between Sta. 1 and Sta. 2. The wire numbered 13 isconnected at cs with terminal 3 and at 0.9 with terminal 1 and is theindependent wire between Sta. 1 and Sta. 3. The wire numbered 23 isconnected at 08 with terminal 3 and at cs with terminal2 and is theindependent wire between Sta. 2 and Sta. 3, and so on in like mannereach of the independent wires are numbered. The independent wire in eachcase, together with the common wire, forms a complete electrical circuitbetween the two stations in which the independent wire terminates.

The keys are represented in Fig. 1 in the typical manner commonlyemployed intelephone drawings. The keys at Sta. 1 are designated 7c and7c, because they are the keys at Sta. 1 which connect through theterminals on the connecting-strip 08 to the circuits leading,respectively, to Sta. 2 and Sta. 3, the keys at Sta. 2 are designated 7cand Jr, because they are the keys at Sta. 2 which connect through theterminals on the connecting-strip 03 to the circuits leading, re-

spectively, to Sta. 1 and Sta. 3, and the keys signal-receiving group.The outside contactsprings, which in each case are connected to thetelephone and signal-sending group, are normally open.

Located just above and directly connected to the inside contact-springsof each key is a visual signal or drop. The drops at Sta. 1 aredesignated d and 61", because they are the drops located at Sta. 1 whichindicate, respectively, calls from Stas. 2 and 3, those at Sta. 2 aredesignated d and ti, because they are the drops at Sta. 2 whichindicate, respectively, calls from Stas. 1 and 3, and those at Sta. 3are designated d and d, because they are the drops at Sta. 3 whichindicate, respectively, calls from Stas. 1 and 2.

A magneto-electric bell is located at each of the Stas. 1, 2, and 3 anddesignated, respectively, m, m, and m. The magnetobell is the audiblesignal forming a part of the ignal-receiving group at each station.

The transmitters t, t, and t, the receivers r, r, and r, theinduction-coils i, c', and i, the primary battery I), b, and b, and thereceiver-hooks h, h, and h are located, respectively, at each of theStas. 1, 2, and 3. They form at each of the stations the telephone setproper and are a part of the telephone and signal-sending group.

A magneto-electric generator is located at each of the Stas. 1, 2, and 3and designated, respectively, g, g, and They are at each of the stationsa part of the telephone and signal-sending group All of the detail partsof the generators being well known are not shown; but it may be well inthis connection to explain that while the wire 11 is constantlyconnected with one end of the armature-winding the wire 33 only makescontact with the other end of the armature-coil when the crank c isoperated, the operation of the crank electrically closing a pair ofnormally open contacts in the usual manner.

It is unnecessary to explain further details of the construction of thesystem, and therefore the operation may now be explained.

Let it be assumed that Sta. 1 desires to call and talk with Sta. 3. Theparty at Sta. 1 throws the key k that is, the key the movable arms A Aof which connect to the circuit leading to Sta. 3into the otherposition. All the details of the keys are not represented because wellknown; but for the purpose of explaining the operation it may be assumedthat when the key It? is thrown into the other position the wedge w ispushed in directly between the movable arms A A far enough to cause themto break contact with the inside sp *ings and make contact with theoutside pair of springs and to remain in that position until such timeas it is desired to throw the key hack into the normal position. hen thekey 7/ is thrown into the position as described above, the signalreceiving group is disconnected from and the telephone andsignal-sending group connected with the circuit O0 13 leading to Sta. 3.order to signal Sta. 3 the party at Sta. 1 turns the crank c of hisgenerator g and by tracing the wires leadingfrom the generator g, one,11, making circuit with wire 22 through the contact n of thereceiver-hook h, the other, 33, leading direct to the key 7c, and,remembering the changed position of the key It, it will be seen that thealternating current generated passes out over the circuit 0O 13 leadingto Sta. 3. Having traced the path of the current passing through the key15 and leading out from Sta. 1 over the terminals 0, 3 on theconnecting-strip es, the out-side wires 0O 1*3 bring the current intoSta. 3 over the terminals 0, 1 of the connecting-strip as and passing onthrough the key 7c which is of course in the normal position asindicated in the drawings, the circuit is closed through the winding eof the drop (Z That which takes place at Sta. 3 is that when thealternatingcurrents passing through the winding o of the drop d, magnetizing the core 12', which at pole e alternately attracts and repelsthe armature a and causes the armfto vibrate, thereby instantlyreleasing the brass shutter s, which falls forward, disclosing on theface of the drop (Z the number of the station calling and also closingthe commonly-called night-bell con tact at" at the terminal 2;, wherebythe magneto-bell m is thrown into multiple circuit with drop dcontinuing to ring as long as the party at Sta. 1 continues to turn thegenerator g. Having si naled Sta. 3, the party at Sta. 1 lifts hisreceiver 9" from the hook it and places it to his ear. The receiver-hookit being released is lifted by the spring Z, thus breaking contact at n,cutting the generator g out of circuit, and also making contact at 79and thereby closing the telephone set at Sta. 1 with the circuit whichhas just been traced leading to Sta. 3. The party at Sta. 3 havingreceived the signal from Sta. 1 may restore the shutter s of the drop dtaking note of the number, throw the key 7% corresponding to it into theother position, and lift his receiver r from the hook it, whereby he isthen in actual telephone connection with the party at Sta. 1. In

throwing the key 1/ into the other position the party at station 3 cutsthe signal-receiving Then in group out of circuit and connects thetelephone signal-sending group into circuit with the wires leading toSta. 1 in the same manner as the key it was operated at Sta. 1, and whenthe receiver 1 is removed the hook h being released cuts the generatorout of circuit and switches the telephone set into circuit in the samemanner as the hook h operated at Sta. 1. When the two'parties havefinished talking, each returns his receiver to the hook and restores thekey, which he has thrown into reverse position, back into the normalposition, and each party is then ready to again be signaled.

It will be noticed that when one party calls another, as the party atSta. 1 called Sta. 3, that the party calling does not get actualtelephone connection with the party called until the party being calleddesires to connect him into circuit for that purpose. So that it whileStas. 1 and 3 were in conversation the party at Sta. 2 should call Sta.1, for instance, the party at Sta. 1 need not connect Sta. 2,intocircuit while talking with Sta. 3. The party at Sta. 2 may lift hisreceiver from the hook after having thrown the key for talking to Sta.1, thereby connecting his own telephone set in on the circuit lead ingto Sta. 1; but he will merely be listening in on the drop andmagneto-bell at Sta. 1 as long as the keyat Sta. 1 corresponding to thecircuit leading to Sta. 2 remains in the normal position, and the partyat Sta. 2 will therefore be unable to hear the conversation betweenStas. 1 and 3. The party at Sta. 1 may say to the party at Sta. 3 Holdthe wire one minute, and instantly switch Sta. 3 out of circuit andswitch Sta. 2 into circuit with his own set and say to the party at Sta-2 "Am busy will call you, and as quickly cut Sta. 2 out of circuit andSta. 3 into circuit, again resuming his conversation with the party atSta. 3. It is not necessary, however, that the party at Sta. 1 shouldcut Sta. 3 out of circuit while answering Sta. 2, and the party at Sta.2 may even become aparty to a general conversation between the party atSta. 1, the party at Sta. 3, and himself.

The construction of the system and its operation as already explainedillustrate its uses sufiiciently well. Other forms, however, ofapparatus which accomplish similar results may be substituted for theexact forms shown in the drawings without altering the basic principlesof the inventionviz., the disposition of the local circuits, thearrangement of the interconnecting circuits, and the method ofswitching. In any case the telephone when in use is maintained in anindependent balanced local circuit. The interconnecting circuitscomprise independent circuits for respectively connecting each stationwith each one of the remaining stations, and in the method of switchingtwo operations are always necessary to connect the telephones of twostations together-namely, the operation of the switches at the stationcalling and ,the operation of the switches at the station called.

It is obvious that earth return may be substituted for the metalliccommon return shown in the drawings; but the danger of line disturbanceswould be increased thereby, and it is doubtful whether the saving of onewire would in any case justify the change. Attention is directed to thefact that in Fig. 2 the common return-wire is a complete loop4l. 6., itis continuous in one direction from each station to every other stationand back to the first-mentioned station from the other direction. Thisis thought to be an advantage, as the return is thus completed betweenany two stations in two directions and the liability of cross-talkincidental to the use of a common return lessened without increasing thesize of the conductor. If the common return-wire were broken at any onepoint in the loop, service would not be interrupted. Attention isfurther directed to the fact that in Fig. 2 the interconnecting linesbranch about equally in two directions from each station. In this way auniform-sized cable can be used throughout which has a less number ofconductors than will be required between most of the stations when thecab1eloop is not continouous and complete. This plan also secures toeach independent line the shortest distance of paralleling any one ofthe other independent lines, thus lessening the chances of cross-talk byinduction between the independent lines, and the plan may always beconveniently used where the stations are not all located at points in aright line, which is rarely the case. Furthermore, this plan is cheaperthan twin-pair twisted or transposed metallic circuits between thestations and for ordinary distances has been found to be equally as freefrom cross-talk.

I am aware that various other inventors have made use of independentwires for respectively connecting each station with each one of theother stations, but no one, so far as I know, has taken all theprecautions necessary to secure absolute privacy in communications as Ihave done. To overhear conversations by induction destroys secrecy justas efiectively as being able to cut in on the circuits.

By the use of the term local in this specification in reference to thewiring it is intended to distinguish the wiring at each station from theinterconnecting lines. The interconnecting wires are considered to losetheir identity as such in the first piece of apparatus they connect toat each station, which is essential to the proper operation of thesystemviz., the switches. The connecting-strips are only used forconvenience in keeping trace of the wires at each station and may beentirely omitted. It is not, however, intended to be inferred by the useof the word local that the circuits so designated are secondary incharacter.

I claim as my invention 1. An intercommunication telephone systemconsisting of the combination of interwiring connecting three or morestations with one another, telephone apparatus at each station,signal-sending apparatus at each station, a separate group of wiring forsaid telephone and signal-sending apparatus, located at each station,signal-receiving apparatus and a separate group of wiring therefor ateach station, and devices at the respective stations for electricallyconnecting the interwiring between any two stations, first to one groupof wiring at one station, and then to the other group at the samestation, said interwiring comprising independent wires for respectivelyconnecting the apparatus at each one of the stations, with the apparatusat each one of the remaining stations. 1

2. An intercommunication telephone system consisting of the combinationof interwiring connecting three or more stations with one another,telephone apparatus at each station, signal-sending apparatus at eachstation, a group of wiring for said telephone and signal-sendingapparatus, located at each station, signal-receiving apparatus and agroup of wiring therefor at each sta tion, and devices at the respectivestations for electrically connecting the interwiring between any twostations, first to one group of wiring at one station, and then to theother group at the same station, said interwiring consisting of a commonreturn-wire for all the stations, and independent wires respectivelyconnecting the apparatus at each one of the stations, with the apparatusat each one of the remaining stations, said devices consisting of aswitch, two of whose terminals are connected to said interwiring, two toone of said groups, and the remaining two to the other group.

3. An intercommunication telephone system consisting of the combinationof interwiring connecting three or more stations with one another,telephone apparatus at each station, signal-sending apparatus at eachstation, a group of wiring for said telephone and signal-sendingapparatus, located at each station, signal-receiving apparatus and agroup of wiring therefor at each station,

and devices at the respective stations for electrically connecting theinterwiring between any two stations, first to one group of wiring atone station, and then to the other group at the same station, saidinterwiring consisting of a common returnwire for all the stations, andindependent wires respectively connecting the apparatus at each one ofthe stations, with the apparatus at each one of the remaining stations,said devices consisting of a switch, two of whose terminals areconnected to said interwiring, two to one of said groups, and theremaining two to the other group, and a wedge for controlling theconnections of all the terminals.

4. An intercommunieation telephone system consisting of the combinationof telephone and signal apparatus, located at each of three or morestations, a system of interconnecting lines comprising independent wiresfor connecting each station respectively with each one of the otherstations, a system. of local wiring for connecting up the apparatus ateach station, which last-named system includes an independent balancedcircuit for the telephone apparatus, and electric switches at eachstationfor cutting in the said telephone apparatus at that station onany pair of wires, while maintaining it disconnected from any of theother pairs of wires, whereby when any two stations are telephonicallyconnected, no other station can listen in to either said two stations.

5. An intercommunication telephone sys tem consisting of the combinationof telephone and signal apparatus, located at each of three or morestations, at system of interconnecting lines comprising independentwires for connecting each station respectively with each one of theother stations, a system of local wiring for connecting up the apparatusat each station, said last-named system including an independentbalanced circuit for the telephone apparatus, and electric switches ateach. station for cutting" in the said telephone apparatus at thatstation on any pair of wires, while maintaining it disconnected from anyof the other pairs of wires, whereby when any two stations aretelephonicallyconnected, no other station can listen in to either saidtwo stations, said telephone apparatus consisting of a transmitter,receiver and induction-coil located at each of said stations, and anelectric generator for supplying a current to said telephone apparatus,and said signal apparatus consisting of a single audible signal locatedat each of said stations, as many visual signals at each station, asthere are stations less one, and an electric generator for operatingsaid signal apparatus.

6. An intercommunication telephone sys tem consisting of the combinationof telephone, signal-sending and signal-receiving apparatus, located ateach of three or more stations, a common return-wire for the apparatusat all the stations, and independent wires respectively connecting theapparatus at each one of the stations with the apparatus at each one ofthe remaining stations, two groups of local wiring at each station, keysat each station, each group of wiring being connected to a separate pairof contact springs on the keys by an independent pair of wires, onegroup including the telephone and signal-sending apparatus, switchingcontacts located in and forming a part of the apparatus located in thislast-named group, the other group being the signal-receivmg group ofwiring, and including visual signals and an audible signal, otherswitching contacts forming a part of each visual mechanism and operatedthereby, the audible signal being connected in multiple with each visualsignal through each pair of said switching contacts, whereby the audiblesignal may operate simultaneously with any one of the visual signals.

7. An intercommunication telephone system, consisting of a telephoneinstrument located at each of three or more difierent sta tions, signalsat each station, a device at each station for operating the signals ateach one of the other stations, a system of interconnecting linescomprising independent wires, for connecting the apparatus at eachstation respectively with the apparatus at each one of the otherstations, and means at each station for including any of said apparatusin circuit with the interconnecting lines leading to any other station,said means, when connected for telephoning, including only the telephoneinstrument in said circuit, said telephone instrument being connectedwith said means in a balanced independent local circuit, while thesignals alone are included in circuit with the wires leading to theother stations, whereby complete privacy is secured between any two ormore telephones which are connected for telephoning and at the same timeeach busy station is maintained available to be signaled by otherstations.

8. An intercommunication telephone system consisting of the combinationof telephone, signal-sending, signal-receiving and switching apparatus,a system of interwiring connecting the above elements, said telephoneapparatus consisting of a telephone instrument located at each of threeor more stations, said signal-sending apparatus comprising a device ateach of said stations for operating signals at any other station, saidsignal-receiving apparatus including signals at each station to indicatethe station. from which the signals are operated, and the said switchingapparatus consisting of a means at each station for cutting in, eitherthe said telephone apparatus at that station, or the said signal-sendingapparatus, on any pair of wires, while maintaining it disconnected fromany of the other pairs of wires, and for simultaneously cutting out thesignal-receiving apparatus at the same said station from the saidfirst-named pair of wires, and a balaneed independent local circuit forthe said telephone apparatus at each station and in which said telephoneis wired to said means.

9. An intercommunication telephone-system consisting of the combinationof interwiring connecting three or more stations with one another,telephone apparatus at each station, signal sending apparatus at eachstation, a separate group of wiring for said telephone andsignal-sending apparatus, located at each station, signal-receivingapparatus including a means for indicating the stations from whichsignals come, and a separate group of wiring therefor at each station,and devices at the respective stations for electrically connecting theinterwiring between any two stations, first to one group of wiring atone station, and then to the other group at the same station.

10. Anintercommunication telephone system consisting of the combinationoftelephone and, signal apparatus, located at each of three or morestations, a common return-wire for all the stations, a single wireconnection from each station to each other station, a system of localwiring for connecting up the apparatus at each station, said last-namedsystem including an independent balanced circuit for the telephoneapparatus, and electric switches at each station for cutting in the saidtelephone apparatus at that station on any one or more of the pairs ofwires, while maintaining it disconnected from any of the other pairs ofwires, whereby when any two or more stations are telephonicallyconnected, no other station can listen in on the circuit connecting saidtwo or more stations.

1 1. An intercommunication telephone system consisting of thecombination of telephone and signal apparatus, located at each of threeor more stations, a common returnwire for all the stations, a singlewire con nection from each station to each other station, a system oflocal wiring for connecting up the apparatus at each station, saidlastnamed system including an independent balanced circuit for thetelephone apparatus, and electric switches at each station for cuttingin the said telephone apparatus at that station on any one or more ofthe pairs of wires, while maintaining it disconnected from any of theother pairs of wires, whereby when any two or more stations are telehon-.

ically connected, no other station can isten in on the circuitconnecting said two or more stations, said telephone apparatus consistinof a transmitter, receiver and induction-00' located at each of saidstations, and an elec tric generator for supplying a current to saidtelephone apparatus, and said signal ap aratus consisting of a singleaudible signal 0- cated at each of said stations, as many visual signalsat each station, as there are stations less one, and an electricgenerator for operating said signal apparatus. a

12. An intercommunication telephone system consisting of the combinationof telephone and signal apparatus, located at each of three or morestations, a common returnwire for all the stations, a single wireconnection from each station to each other station, a system of localw1r1ng for connecting up the apparatus at each station, and elec- I-with one another, telephone apparatus at each station, signal-sendingapparatus at each station, a separate group of wiring for said telephoneand signal-sending apparatus, located at each station, signal-receivingapparatus and a separate group of wiring therefor at each station, anddevices at the respective stations for electrically connecting theinterwiring between any two stations, first to the signal-receivinggroup of wiring at one station, and then to the telephone andsignalsending group of wiring at the same station, said interwiringcomprising independent wires for respectively connecting the apparatusat each one of the stations, with the apparatus at each one of theremaining stations.

14. An intercommunication telephone system consisting of the combinationof tele phone, signal-sending, signal-receiving and switching apparatus,a system of interwiring connecting the above elements, said telephoneapparatus consisting of a telephone instrument located at each of threeor more sta tions, said signal-sending apparatus comprising a device ateach of said stations for operating signals at any other station, saidsignal-receiving apparatus including signals at each station to indicatethe station from which the signals are operated, independent IIO localcircuits for the telephone apparatus and for the signal-receivingapparatus, a local circuit for the signal-sending apparatus in multiplewith the telephone local circuit, the said switching apparatusconsisting of a means at each station for cutting in either the saidtelephone apparatus at that station, or the said tions, saidsignal-sending apparatus comprising a device at each of said stationsfor operating signals at any other station, said signal-receivingapparatus including signals at each station to indicate the station fromwhich the signals are operated, and the said switching apparatusconsisting of a means at each station for cutting in the said telephoneapparatus at that station on any one or more of the pairs of wires,while maintaining it disconnected from any of the other pairs of wires,and for simultaneously cutting out both the signal-sending and thesignal-receiving apparatus at the same said station from the saidfirst-named one or more pairs of wires.

16. An intercommunication telephone system consisting of the combinationof telephone, signal-sending, signal-receiving and switching apparatus,a system of interwiring connecting the above elements, said telephoneapparatus consisting of a telephone instrument located at each of threeor more stations, said signal-sending apparatus comprising a device ateach of said stations -for operating signals at any other station, saidsignal-receiving apparatus including signals at each station to indicatethe station from which the signals are operated, and the said switchingapparatus consisting of a means at each station for cutting in, eitherthe said telephone or si nal-sending apparatus, or the saidsignal-receiving apparatus at that station, on any pair of wires, whilemaintaining it disconnected from any of the other apparatus at the samestation, and when the said telephone apparatus is cut in on the said anypair of wires, maintaining it in a balanced local circuit.

17. In an intercommunication telephone system, two groups of localwiring at each station, keys at each station, each group of wiring beingconnected to a separate pair of contact-springs on the keys by anindependent pair of wires, one group including the telephone andsignal-sending apparatus, switching contacts located in and forming apart of the apparatus located in this last-named group, the other groupbeing the signal-re ceiving group of wiring, and including visualsignals and an audible signal, other switching contacts forming a partof each visual mechanism and operated thereby, the audi ble signal beingconnected in multiple with each visual signal through each pair of saidswitching contacts, whereby the audible signal may operatesimultaneously with any one of the visual signals. I

18. In an interconnnunication telephone system between three or morestations, an organization of interconnecting lines comprisingindependent wires for respectively connecting any one of said stationswith either one of the other stations, a telephone at each station andnormally out of circuit, a balanced local circuit at each station and inwhich said telephone is maintained when connected with any of saidinterconnecting lines, and separate switches at each station, one forconnecting each interconnecting line with the said telephone, and toconnect any two telephones at different stations together over thecorresponding interconnecting line it being necessary to close two ofsaid switches, one switch at the station calling and one switch at thestation called, whereby, when any two or more of said stations aremutually connected together in a circuit for telephoning, no otherstation can connect in or listen 011 the last-named circuit.

19. An intercoinmunication telephone system consisting of thecombination of interwiring connecting three or more I stations with oneanother, telephone apparatus at each station, signal-sending apparatusat each station, a group of wiring for said telephone and signal-sendingapparatus, located at each station, signal-receiving apparatus and agroup of wiring therefor at each station, and devices at the respectivestations for electrically connecting the interwiring between any twostations, first to one group of wiring at one station, and then to theother group at the same station, said interwiring comprising independentwires, for respectively connecting the apparatus at each one of thestations, with the apparatus at each one of the remaining stations, saiddevices consisting of a switch, two oi whose terminals are connected tosaid interwiring, two to one of said groups, and the remaining two tothe other group.

20. An intercommunication telephone system consisting of the combinationof inter wiring connecting three or more stations with one another,telephone apparatus at each station, signal-sending apparatus at eachstation, a group of wiring for said telephone and signal-sendingapparatus, located at each station, signal-receiving apparatus and agroup of wiring therefor at each station, and devices at the respectivestations for electrically connecting the interwiring between any twostations, first to one group of wiring at one station, and then to theother group at the same station, said interwiring comprising independentwires, for respectively connecting the apparatus at each one of thestations, with the apparatus at each one of the remaining stations, saiddevices consisting of a switch, two of whose terminals are connected tosaid interwiring, two to one of said groups, and the remaining two tothe other group, and a wedge for controlling the connections of all theterminals.

2 1. An intercomiminication telephone system consisting of thecombination of telecomprising independent wires, for respectivelyconnecting the apparatus at each one of the stations with the apparatusat each one of the remaining stations, two groups of local wiring ateach station, keys at each station, each group of wiring being connectedto a separate pair of contact-springs on the keys by an independent pairof wires, one group including the telephone and signalsending apparatus,switching contacts located in and forming a part of the apparatuslocatedin this last-named group, the other group being the signal-receivinggroup of wiring, and including visual signals and an audible signal,other switching contacts forming a part of each visual mechanism andoperated thereby, the audible signal being connected in multiple witheach visual si nal through each pair of said switching contacts, wherebythe audible signal may operate simultaneously with any one of the visualsignals.

22. An intercommunication telephone system consisting of the combinationof interwiring connecting three or more stations with one another,telephone apparatus at each station, signal-sending apparatus at eachstation, a separate group of wiring for said telephone andsignal-sending apparatus, located at each station, signal-receivingapparatus and a separate group of wiring therefor at each station, anddevices at the respective stations for electrically connecting the temconsisting of the combination of interwiring connecting three or morestations with one another, telephone apparatus at each station,signal-sending apparatus at each station, a separate group of wiring forsaid telephone'and signal-sending apparatus,

from the interwiring between said any two stations when the other saidgroup is connected thereto.

24. An intercommunication telephone system consisting of the combinationof inter wiring connecting three or more stations with one another,telephone apparatus at each station, signal-sending apparatus at eachstation, a separate group of wiring for said telephone andsignal-sending apparatus, located at each station, signal-receiving apparatus and a separate group of wiring there for at each station, anddevices at the respective stations for electrically connecting theinterwiring between any two stations, first to the signal-receivinggroup of wiring at one station, and then to the telephone andsignal-sending group of wiring at the same station, and fordisconnecting either of said groups of wiring from the interwiring between said any two stations when the other said group is connectedthereto, said interwiring comprising independent wires for respectivelyconnecting the apparatus at each one of the stations, with the apparatusat each one of the remaining stations.

In testimony whereof I have hereunto subscribed my name this 25th day ofOctober, 1902.

RICHARD M. BEARD.

l/Vitnesses:

GEORGE W RICHARDSON, MARIA WESTON.

